SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e3f2bf6ceadf12a27b9d22916f8ed10e22d1cb6c6b908de5747e6bdd29bf9a0' 
  AND token = '9avFXGrq0uK6HOzhGk0gcwvZngOPJDtMMC8Ng7EUhjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}